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  <title>通过名称获取特定的外部变量，并且可以通过过滤器处理它</title>
 </head>
 <body class="docs"><div id="layout">
  <div id="layout-content"><div id="function.filter-input" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">filter_input</h1>
  <p class="verinfo">(PHP 5 &gt;= 5.2.0, PHP 7)</p><p class="refpurpose"><span class="refname">filter_input</span> &mdash; <span class="dc-title">通过名称获取特定的外部变量，并且可以通过过滤器处理它</span></p>

 </div>
 <div class="refsect1 description" id="refsect1-function.filter-input-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>filter_input</strong></span>
    ( <span class="methodparam"><span class="type">int</span> <code class="parameter">$type</code></span>
   , <span class="methodparam"><span class="type">string</span> <code class="parameter">$variable_name</code></span>
   [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$filter</code><span class="initializer"> = FILTER_DEFAULT</span></span>
   [, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$options</code></span>
  ]] ) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>


 </div>

 <div class="refsect1 parameters" id="refsect1-function.filter-input-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<code class="parameter">type</code></dt>

     <dd>

      <p class="para">
       <strong><code>INPUT_GET</code></strong>, <strong><code>INPUT_POST</code></strong>,
       <strong><code>INPUT_COOKIE</code></strong>, <strong><code>INPUT_SERVER</code></strong>或
       <strong><code>INPUT_ENV</code></strong>之一。
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">variable_name</code></dt>

     <dd>

      <p class="para">
       待获取的变量名。
      </p>
     </dd>

    
    
 
  <dt>
<code class="parameter">filter</code></dt>

  <dd>

   <p class="para">
    The ID of the filter to apply. The <a href="filter.filters.html" class="xref">Types of filters</a>
    manual page lists the available filters.
   </p>
   <p class="para">
    If omitted, <strong><code>FILTER_DEFAULT</code></strong> will be used, which is
    equivalent to
    <a href="filter.filters.sanitize.html" class="link"><strong><code>FILTER_UNSAFE_RAW</code></strong></a>.
    This will result in no filtering taking place by default.
   </p>
  </dd>

 

    
     <dt>
<code class="parameter">options</code></dt>

     <dd>

      <p class="para">
       一个选项的关联数组，或者按位区分的标示。如果过滤器接受选项，可以通过数组的 &quot;flags&quot; 位去提供这些标示。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.filter-input-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   如果成功的话返回所请求的变量。如果过滤失败则返回 <strong><code>FALSE</code></strong> ，如果<code class="parameter">variable_name</code> 不存在的话则返回 <strong><code>NULL</code></strong> 。
   如果标示 <strong><code>FILTER_NULL_ON_FAILURE</code></strong> 被使用了，那么当变量不存在时返回 <strong><code>FALSE</code></strong> ，当过滤失败时返回 <strong><code>NULL</code></strong> 。
   </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.filter-input-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-6180">
    <p><strong>Example #1 一个 <span class="function"><strong>filter_input()</strong></span> 的例子</strong></p>
    <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$search_html&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">filter_input</span><span style="color: #007700">(</span><span style="color: #0000BB">INPUT_GET</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'search'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">FILTER_SANITIZE_SPECIAL_CHARS</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$search_url&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">filter_input</span><span style="color: #007700">(</span><span style="color: #0000BB">INPUT_GET</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'search'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">FILTER_SANITIZE_ENCODED</span><span style="color: #007700">);<br />echo&nbsp;</span><span style="color: #DD0000">"You&nbsp;have&nbsp;searched&nbsp;for&nbsp;</span><span style="color: #0000BB">$search_html</span><span style="color: #DD0000">.\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #DD0000">"&lt;a&nbsp;href='?search=</span><span style="color: #0000BB">$search_url</span><span style="color: #DD0000">'&gt;Search&nbsp;again.&lt;/a&gt;"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
    </div>

    <div class="example-contents"><p>以上例程的输出类似于：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
You have searched for Me &amp;#38; son.
&lt;a href=&#039;?search=Me%20%26%20son&#039;&gt;Search again.&lt;/a&gt;
</pre></div>
    </div>
   </div>
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.filter-input-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="filter_var.html" class="function" rel="rdfs-seeAlso">filter_var()</a> - 使用特定的过滤器过滤一个变量</span></li>
    <li class="member"><span class="function"><a href="filter_input_array.html" class="function" rel="rdfs-seeAlso">filter_input_array()</a> - 获取一系列外部变量，并且可以通过过滤器处理它们</span></li>
    <li class="member"><span class="function"><a href="filter_var_array.html" class="function" rel="rdfs-seeAlso">filter_var_array()</a> - 获取多个变量并且过滤它们</span></li>
    <li class="member"><a href="filter.filters.html" class="xref">Types of filters</a></li>
   </ul>
  </p>
 </div>


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